xorg-server-1.4/hw/xfree86/os-support/misc/SlowBcopy.c

   1 /*******************************************************************************
   2   for Alpha Linux
   3 *******************************************************************************/
   4
   5 /*
   6  *   Create a dependency that should be immune from the effect of register
   7  *   renaming as is commonly seen in superscalar processors.  This should
   8  *   insert a minimum of 100-ns delays between reads/writes at clock rates
   9  *   up to 100 MHz---GGL
  10  *
  11  *   Slowbcopy(char *src, char *dst, int count)
  12  *
  13  */
  14
  15 #ifdef HAVE_XORG_CONFIG_H
  16 #include <xorg-config.h>
  17 #endif
  18
  19 #include <X11/X.h>
  20 #include "xf86.h"
  21 #include "xf86Priv.h"
  22 #include "xf86_OSlib.h"
  23 #include "compiler.h"
  24
  25 static int really_slow_bcopy;
  26
  27 _X_EXPORT void
  28 xf86SetReallySlowBcopy(void)
  29 {
  30         really_slow_bcopy = 1;
  31 }
  32
  33 #if defined(__i386__) || defined(__x86_64__)
  34 static void xf86_really_slow_bcopy(unsigned char *src, unsigned char *dst, int len)
  35 {
  36     while(len--)
  37     {
  38         *dst++ = *src++;
  39         outb(0x80, 0x00);
  40     }
  41 }
  42 #endif
  43
  44 /* The outb() isn't needed on my machine, but who knows ... -- ost */
  45 _X_EXPORT void
  46 xf86SlowBcopy(unsigned char *src, unsigned char *dst, int len)
  47 {
  48 #if defined(__i386__) || defined(__x86_64__)
  49     if (really_slow_bcopy) {
  50         xf86_really_slow_bcopy(src, dst, len);
  51         return;
  52     }
  53 #endif
  54     while(len--)
  55         *dst++ = *src++;
  56 }
  57
  58 #ifdef __alpha__
  59 /*
  60  * The Jensen lacks dense memory, thus we have to address the bus via
  61  * the sparse addressing scheme. Time critical code uses routines from
  62  * BUSmemcpy.c
  63  *
  64  * Martin Ostermann (ost@comnets.rwth-aachen.de) - Apr.-Sep. 1996
  65  */
  66
  67 #ifdef linux
  68
  69 unsigned long _bus_base(void);
  70
  71 #ifdef TEST_JENSEN_CODE /* define to test the Sparse addressing on a non-Jensen */
  72 #define SPARSE (5)
  73 #else
  74 #define SPARSE (7)
  75 #endif
  76
  77 #define isJensen() (!_bus_base())
  78
  79 #else
  80
  81 #define isJensen() 0
  82 #define SPARSE 0
  83
  84 #endif
  85
  86 _X_EXPORT void
  87 xf86SlowBCopyFromBus(unsigned char *src, unsigned char *dst, int count)
  88 {
  89     if (isJensen())
  90     {
  91         unsigned long addr;
  92         long result;
  93
  94         addr = (unsigned long) src;
  95         while( count ){
  96             result = *(volatile int *) addr;
  97             result >>= ((addr>>SPARSE) & 3) * 8;
  98             *dst++ = (unsigned char) (0xffUL & result);
  99             addr += 1<<SPARSE;
 100             count--;
 101             outb(0x80, 0x00);
 102         }
 103     }
 104     else
 105         xf86SlowBcopy(src,dst,count);
 106 }
 107
 108 _X_EXPORT void
 109 xf86SlowBCopyToBus(unsigned char *src, unsigned char *dst, int count)
 110 {
 111     if (isJensen())
 112     {
 113         unsigned long addr;
 114
 115         addr = (unsigned long) dst;
 116         while(count) {
 117             *(volatile unsigned int *) addr = (unsigned short)(*src) * 0x01010101;
 118             src++;
 119             addr += 1<<SPARSE;
 120             count--;
 121             outb(0x80, 0x00);
 122         }
 123     }
 124     else
 125         xf86SlowBcopy(src,dst,count);
 126 }
 127 #endif